This invention relates generally to chucks mounted on spindles of machine tools for holding workpieces. More particularly the invention relates to an automatic oil-supplying or lubricating system of a power chuck for holding and rotating a workpiece, the lubricating system operating to supply positively lubricating oil to the sliding or rubbing surfaces of the chuck requiring lubrication.
A large number of lubricating systems or devices of machine-tool chucks have been proposed heretofore as, for example, in Japanese Utility Model Application Laid-Open (Kokai) No. 179710/1980 and Utility Model Application Laid-Open (Kokai) No. 2306/1981. While the structural organizations of these proposed lubricating systems are respectively different, each system comprises an independent system for carrying out lubrication and requires an oil supply piping path exclusively for lubrication.
An independent lubrication system with an exclusive supply piping is not fully satisfactory since its organization is complicated, and its maintenance is troublesome.